US 2005 0225477 A1 discloses a vehicle collision warning system comprising a road curvature estimation subsystem for estimating the curvature of the roadway using measurements from host vehicle motion sensors, a target state estimation subsystem for estimating the state of a target vehicle on the basis of a radar measurement, and a control subsystem for determining whether or not the host vehicle is at risk of collision with the target, and if so, for determining and effecting corresponding action.
The goal of a pedestrian warning system is to warn the driver of the vehicle if there is a pedestrian on the road ahead of the vehicle or close to the road and walking towards the road. To be able to warn correctly for the pedestrian the system must know where the pedestrian is and where the road is ahead of the vehicle, which is particularly difficult in curves. For a warning to be meaningful for the driver, the warning must be activated several seconds before the predicted time of collision. However, predicting a curved path of the vehicle based on the vehicle dynamics generally works well at most a few hundred milliseconds ahead.